Input: cm109 - validate number of endpoints before using them

commit ac2ee9ba953afe88f7a673e1c0c839227b1d7891 upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer should a malicious device lack endpoints.

Fixes: c04148f915e5 ("Input: add driver for USB VoIP phones with CM109...")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/input/misc/cm109.c b/drivers/input/misc/cm109.c
index ab86051..d5b382c 100644 (file)
--- a/drivers/input/misc/cm109.c
+++ b/drivers/input/misc/cm109.c
@@ -663,6 +663,10 @@ static int cm109_usb_probe(struct usb_interface *intf,
        int error = -ENOMEM;
 
        interface = intf->cur_altsetting;
+
+       if (interface->desc.bNumEndpoints < 1)
+               return -ENODEV;
+
        endpoint = &interface->endpoint[0].desc;
 
        if (!usb_endpoint_is_int_in(endpoint))